Description: (Abstract of the application) The major goal of the imaging core is to facilitate the use of quantitative and qualitative imaging techniques in the analysis of protein interactions at the cellular and molecular level. A wide range of imaging techniques applicable to the study of membrane and cytoskeletal proteins in cells, tissues, whole organs are provided. In addition, the utilization of transgenic technology offers new opportunities to study the phenotypic changes at the integrated whole animal level. New technologies are now available for greater resolution of localization of specific target proteins as well as permitting vital microscopy where dynamic changes can be identified. Paraffin section light microscopy, still the gold standard for the examination of structural phenotypic changes, has been expanded to include localization of specific proteins using immunohistochemistry and of specific mRNAs using in situ hybridization and in situ reverse transcription. Confocal microscopy can be applied to tissues where analyses of changes in intracellular ion concentration can be assessed at the tissue level using ion sensitive fluorochromes resulting in an expansion of the capabilities of video imaging techniques which are applied at the cellular level. The utilization of electron microscopic immunocytochemical techniques has been improved for greater accuracy in localization using immunogold and in situ hybridization techniques. The value of these techniques is enhanced by the availability of digital image analysis systems that permit quantitative morphometric measurements and three-dimensional reconstruction and visualization. These techniques are extremely useful in cellular pathobiology but are not easily accessible to investigators and research trainees without previous training or experience. In addition the selection of the proper technique or combination of techniques requires experience in interpretation and knowledge of the limitations of the method. The imaging core will provide expertise and assistance in the utilization of light, immunofluorescence, confocal, and electron microscopy with particular emphasis on phenotypic and pathologic analysis of transgenic models, immunocytochemistry, vital microscopy and image analysis. The facility will give access to these specialized techniques and to the equipment necessary to apply them and will form a focal point for collaboration between members of the program project. Specifically, the core will provide the facilities, service and education necessary for the efficient application of imaging techniques tailored to the individual research objectives of the various members of the program project.